The goals of this project are to 1) purify the glycoproteins of mammalian type-C viruses, 2) characterize the properties of these proteins biochemically and by radioimmunologic techniques, 3) investigate the expression of endogenous viral gene products in mammalian cells and 4) elucidate cellular mechanisms governing endogenous virus release. BIBLIOGRAPHIC REFERENCES: Hino, S., Stephenson, J. R. and Aaronson, S. A.: Radioimmunoassays for the 70,000 molecular weight glycoproteins of endogenous mouse type C viruses: viral antigen expression in normal mouse tissues. J. Virol. 18: 933-941, 1976. Aaronson, S. A., Stephenson, J. R., Tronick, S. R. and Hino, S.: Immunological analysis of structural polypeptides of woolly monkey-gibbon ape type C viruses: woolly monkey sarcoma virus. In Clemmesen, J. and Yohn, D. S. (Eds.): Comparative Leukemia Research, Bibl. Haemat., 43. Basel, Karger, 1976, pp. 102-109.